Thread protector



March 32,1942. A, L, P RKE 2,2??313 THREAD PROTECTOR Filed Sept. 8, 1959 Patented Mar. 31, 1942 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to a thread protector and more particularly to a molded rubber protector for female threads.

Many units such as pipes, valves, pumps,

strainers, primers, and the like are provided with female pipe thread connections. Heretofore, during the shipping of such parts or while they are lying in stock, it has been customary to screw metal pipe plugs into these connections to prevent the entry of dirt, dust and the like, and also to protect the threads from damage. The parts so protected are generally of sufficient value to warrant the additional cost of the above described protecting plugs. However, cheaper parts, such as fittings, are seldom provided with protecting plugs since the original cost of the fittings is often not a whole lot more than the lost of the plug.

In addition to their high initial cost, metal protecting plugs are sometimes objectionable be cause there is always the possibility that the persons handling the parts may unwittingly screw them in too tight, or without a lubricant, and cause the plug to Efreeze within the boss. This is especially true with aluminum alloy parts.

Accordingly, the primary object of the present invention is to provide an improved thread protector which overcomes the above defined defects. 1 v

A further object of the present invention is to provide a protectorthat is inexpensive to manufacture and can, therefore, be more widely used.

A still further object of the present invention is to provide a thread protector that can be easily inserted and removed with the fingers at all times and that during such operation no damage is done to the threads.

Other objects and advantages of the present invention will be. apparent from the following description taken in connection with the accompanying drawing wherein:

Figure 1 is a transver e sectional view of the thread protector as applied to a threaded part.

Figure 2 is a transverse sectional view showing how the annular head on the protector will cross the thread.

Figure 3 is an end view of the protector.

Figure 4 is a side view thereof. I

Figure 5 is a side view of a protector showing a slightly modifledform of the invention.

Referring to the drawing in detail wherein like numerals designate like parts throughout the several views, numeral G-designates a threaded element representative of any female threaded member to which a protector I is to be applied. The threaded element 6 includes threaded portion 8 and an upper face 9. The protector I formed of molded rubber or like flexible material, comprises a cylindrical portion Ill having a bead H at its lower end. The cylindrical portion I is hollowed out at l2 and closed at its upper end by a wall [3.

The wall I3 has its outer face crown shaped and is provided with a pair of ribs l which provide a finger grip for turning the protector into and out of the threaded boss. The wall l3 also includes a flange M which bears against face 9 of the threaded element and limits the inner movement of the protector. A plurality of serrations IB are provided along the edge of the crown portion to further aid in the manipulation of the protector.

As seen in Fig. 4, the bead is formed parallel to the under surface of flange I 4. Since the thread on the threaded member is helical. the bead cannot follow the thread on the entire diameter but due to its flexibility will cross the thread as seen in Fig. 2. This cross threading does no harm to the protector and-actually increases the locking friction to prevent the protector from jarring or vibrating itself loose.

In Figure 5 I have shown a slightly modified form of the protector wherein the lower end of the cylindrical wall portion is provided with a threaded portion il in place of the bead ll shown in the preferred form. In all other re- A thread protector for an internally threaded outlet, comprising a body portion formed wholly from resilient material, said body portion being of uniform diameter and of substantially the same diameter as the inner diameter of the threaded outlet, said bodyportion being hollow and closed at its outer end and provided with a projecting flange which overlies and contacts with the end of the outlet, said body portion having a projecting rib on the exterior thereof and at the inner end of the body, said ribencircling the body and being of a width so as to fitbetween the threads of the outlet for holding the protector in the outlet with the flange in contact with the end of the outlet.

ARTHUR L. PARKER. 

